Variable displacement swash plate type compressor

ABSTRACT

In the compressor of the present invention, first and second recessed strip portions are recessed in a second supporting member. First and second annular members are respectively provided in the first and second recessed strip portions. The first and second annular members respectively include joint gap formed by first to third cutouts. The third cutouts function as aperture in the first and second annular members. The first and second annular members respectively move in the first and second recessed strip portions according to a pressure difference between a pressure regulation chamber and a swash plate chamber. Consequently, the compressor adjusts a flow rate of a refrigerant circulating from the pressure regulation chamber to the swash plate chamber and adjusts a supply amount of lubricant supplied to a second sliding bearing and the like.

TECHNICAL FIELD

The present invention relates to a variable displacement swash platetype compressor.

BACKGROUND ART

Japanese Patent Laid-Open No. 8-105384 discloses a conventional variabledisplacement swash plate type compressor (hereinafter referred to ascompressor). In the compressor, a housing is formed by a front housing,a cylinder block, and a rear housing. A suction chamber and a dischargechamber are respectively formed in the front housing and the rearhousing. A pressure regulation chamber is formed in the rear housing.

In the cylinder block, a swash plate chamber, a plurality of cylinderbores, and a center bore are formed. The center bore is formed on a rearside of the cylinder block.

A drive shaft is inserted through the housing and is rotatably supportedin the housing. A swash plate rotatable by the rotation of the driveshaft is provided in the swash plate chamber. A link mechanism thatallows a change in an inclination angle of the swash plate is providedbetween the drive shaft and the swash plate. Here, the inclination angleis an angle formed by the swash plate with respect to a directionorthogonal to a rotational axis of the drive shaft.

In the respective cylinder bores, pistons are respectively accommodatedto be reciprocatingly movable. Compression chambers are respectivelyformed in the cylinder bores. A conversion mechanism is configured toreciprocatingly move the pistons in the cylinder bores at a strokecorresponding to the inclination angle according to the rotation of theswash plate. An actuator is capable of changing the inclination angle. Acontrol mechanism is configured to control the actuator.

The actuator includes a first movable body, a second movable body, athrust bearing, and a control pressure chamber. The first movable bodyis arranged in the center bore and is movable in the center bore in arotational axis direction. In the first movable body, a shaft hole,through which a rear end portion of the drive shaft is inserted, isformed. Consequently, the rear end portion of the drive shaft isrotatable in the shaft hole of the first movable body. An O-ring and apair of sealing rings are provided between the outer circumferentialsurface of the first movable body and the inner circumferential surfaceof the center bore.

The second movable body is inserted through the drive shaft. The secondmovable body is arranged in the front of the first movable body and ismovable in the rotational axis direction. The thrust bearing is providedbetween the first movable body and the second movable body.

The control pressure chamber is formed on the rear end side of thecenter bore because the first movable body is arranged in the centerbore. The control pressure chamber communicates with the pressureregulation chamber. The pressure regulation chamber and the controlpressure chamber are partitioned from the swash plate chamber by theabove explained the O-ring and the sealing rings.

The control mechanism performs communication control between the controlpressure chamber and the suction chamber and performs communicationcontrol between the control pressure chamber and the discharge chamberto thereby regulate the pressure of a refrigerant in the controlpressure chamber.

In the compressor, the control mechanism is capable of moving the firstand second movable bodies and the thrust bearing in the rotational axisdirection by regulating the pressure of the refrigerant in the controlpressure chamber. Consequently, in the compressor, the link mechanismallows a change in the inclination angle of the swash plate and iscapable of changing a discharge capacity per one rotation of the driveshaft.

However, in the above explained conventional compressor, there is aconcern that lubrication between the drive shaft and the shaft hole isinsufficient, seizure occurs here, and durability is deteriorated.

The present invention has been devised in view of the above explainedthe actual situations in the past and a problem to be solved by thepresent invention is to provide a variable displacement swash plate typecompressor capable of displaying high durability in a compressor thatchanges a discharge capacity using an actuator.

SUMMARY OF THE INVENTION

A variable displacement swash plate type compressor of the presentinvention comprises: a housing in which a suction chamber, a dischargechamber, a swash plate chamber, and a cylinder bore are formed; a driveshaft rotatably supported by the housing; a swash plate rotatable in theswash plate chamber by the rotation of the drive shaft; a link mechanismprovided between the drive shaft and the swash plate and configured toallow a change in an inclination angle of the swash plate with respectto a direction orthogonal to a rotational axis of the drive shaft; apiston accommodated to be reciprocatingly movable in the cylinder bore;a conversion mechanism configured to reciprocatingly move the piston inthe cylinder bore at a stroke corresponding to the inclination angleaccording to the rotation of the swash plate; an actuator capable ofchanging the inclination angle; and a control mechanism configured tocontrol the actuator. The swash plate chamber communicates with thesuction chamber. The actuator includes: a fixed body fixed to the driveshaft in the swash chamber; a movable body movable in the rotationalaxis direction in the swash plate chamber; and a control pressurechamber defined by the fixed body and the movable body and configured tointroduce a refrigerant including lubricant in the discharge chamber tothereby move the movable body. In the housing, a pressure regulationchamber that communicates with the discharge chamber and the controlpressure chamber and a shaft hole that allows the swash plate chamberand the pressure regulation chamber to communicate with each other areformed. In the shaft hole, a bearing rotatably supporting the driveshaft is arranged. A communication path that allows the pressureregulation chamber and the swash plate chamber to communicate with eachother via the bearing is provided between the drive shaft and the shafthole. In the communication path, an annular member arranged around thedrive shaft is provided. The annular member includes an aperture thatallows the pressure regulation chamber and the swash plate chamber toalways communicate with each other. The annular member moves in thecommunication path on the basis of a pressure difference between thepressure regulation chamber and the swash plate chamber to therebyadjust a flow rate of the refrigerant circulating through thecommunication path.

Other aspects and advantages of the present invention will be apparentfrom embodiments disclosed in the attached drawings, illustrationsexemplified therein, and the concept of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view at a time of a maximum capacity in acompressor in embodiment 1.

FIG. 2 is a schematic diagram showing a control mechanism, according tothe compressor of embodiment 1.

FIG. 3 is an essential part enlarged sectional view showing rear endportion of a drive shaft, according to the compressor of embodiment 1.

FIG. 4A is a top perspective view showing first and second annularmembers, according to the compressor of embodiment 1.

FIG. 4B is an essential part enlarged front view showing the first andsecond annular members, according to the compressor of embodiment 1.

FIG. 4C is an enlarged sectional view seen in a direction of arrows C-Cin FIG. 4B.

FIG. 5A is an essential part enlarged sectional view showing a positionof the first annular member in a first recessed strip portion and aposition of the second annular member in a second recessed strip portionand showing positions of the first and second annular members in a statein which a pressure difference between a pressure regulation chamber anda swash plate chamber is large, according to the compressor ofembodiment 1.

FIG. 5B is an essential part enlarged sectional view showing a positionof the first annular member in a first recessed strip portion and aposition of the second annular member in a second recessed strip portionand showing positions of the first and second annular members in a statein which the pressure difference between the pressure regulation chamberand the swash chamber is small, according to the compressor ofembodiment 1.

FIG. 6 is a sectional view at a time of a minimum capacity in thecompressor in embodiment 1.

FIG. 7 is an essential part enlarged sectional view showing a rear endportion of a drive shaft, according to a compressor of embodiment 2.

FIG. 8A is a top perspective view showing the first and second annularmembers, according to a compressor of embodiment 3.

FIG. 8B is an essential part enlarged front view showing the first andsecond annular members, according to a compressor of embodiment 3.

FIG. 8C is an enlarged sectional view seen in a direction of arrow C-Cin FIG. 8B.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Embodiments 1 to 3 embodying the present invention are explained belowwith reference to the drawings. Compressors in embodiments 1 to 3 arevariable displacement swash plate type compressors. All of thecompressors are mounted on a vehicle and configure a refrigerationcircuit of an air-conditioning apparatus for a vehicle.

Embodiment 1

As shown in FIG. 1, the compressor in embodiment 1 includes a housing 1,a drive shaft 3, a swash plate 5, a link mechanism 7, a plurality ofpistons 9, a pair of shoes 11 a and 11 b, an actuator 13, and a controlmechanism 15 shown in FIG. 2.

As shown in FIG. 1, the housing 1 includes a front housing 17 located inthe front of the compressor, a rear housing 19 located in the rear ofthe compressor, first and second cylinder blocks 21 and 23 locatedbetween the front housing 17 and the rear housing 19, and first andsecond valve forming plates 39 and 41.

In the front housing 17, a boss 17 a projecting forward is formed. Ashaft seal device 25 is provided in the boss 17 a. In the front housing17, a first suction chamber 27 a and a first discharge chamber 29 a areformed. The first suction chamber 27 a is located on the innercircumferential side of the front housing 17. The first dischargechamber 29 a is formed in an annular shape and is located on the outercircumferential side of the first suction chamber 27 a in the fronthousing 17.

Further, in the front housing 17, a first front side communication path18 a is formed. The front end side of the first front side communicationpath 18 a communicates with the first discharge chamber 29 a. The rearend side of the first front side communication path 18 a opens to therear end of the front housing 17.

In the rear housing 19, the above explained control mechanism 15 isprovided. In the rear housing 19, a second suction chamber 27 b, asecond discharge chamber 29 b, and a pressure regulation chamber 31 areformed. The pressure regulation chamber 31 is located in a centerportion of the rear housing 19. The second suction chamber 27 b isformed in an annular shape and is located on the outer circumferentialside of the pressure regulation chamber 31 in the rear housing 19. Thesecond discharge chamber 29 b is also formed in an annular shape and islocated on the outer circumferential side of the second suction chamber27 b in the rear housing 19.

Further, in the rear housing 19, a first rear side communication path 20a is formed. The rear end side of the first rear side communication path20 a communicates with the second discharge chamber 29 b. The front endside of the first rear side communication path 20 a opens to the frontend of the rear housing 19.

A swash plate chamber 33 is formed between the first cylinder block 21and the second cylinder block 23. The swash plate chamber is located insubstantially the center in the front-rear direction in the housing 1.

In the first cylinder block 21, a plurality of first cylinder bores 21 aare formed in the circumferential direction at equal angle intervals inparallel to one another. In the first cylinder block 21, a first shafthole 21 b, through which the drive shaft 3 is inserted, is formed. Inthe first shaft hole 21 b, a first sliding bearing 22 a is provided.Note that a roller bearing may be provided instead of the first slidingbearing 22 a.

Further, in the first cylinder block 21, a first recessed portion 21 ccommunicating with the first shaft hole 21 b and coaxial with the firstshaft hole 21 b is formed. The first recessed portion 21 c communicateswith the swash plate chamber 33 and forms a part of the swash platechamber 33. The first recessed portion 21 c is formed in a shape reducedin diameter stepwise toward the front end. At the front end of the firstrecessed portion 21 c, a first thrust bearing 35 a is provided. Further,in the first cylinder block 21, a first communication path 37 a, whichallows the swash plate chamber 33 and the first suction chamber 27 a tocommunicate with each other, is formed. In the first cylinder block 21,a first retainer groove 21 e, which regulates a maximum opening degreeof first suction reed valves 391 a explained below, is recessed.

Further, in the first cylinder block 21, a second front sidecommunication path 18 b is formed. The front end of the second frontside communication path 18 b opens to the front end side of the firstcylinder block 21. The rear end of the second front side communicationpath 18 b opens to the rear end side of the first cylinder block 21.

In the second cylinder block 23, as in the first cylinder block 21, aplurality of second cylinder bores 23 a are formed. The second cylinderbores 23 a form pairs with the first cylinder bores 21 a in the frontand the rear. The first cylinder bores 21 a and the second cylinderbores 23 a are formed in the same diameter.

In the second cylinder block 23, a second shaft hole 23 b, through whichthe drive shaft 3 is inserted, is formed. The second shaft hole 23 bcommunicates with the pressure regulation chamber 31 on the rear endside. The second shaft hole 23 b is equivalent to the shaft hole in thepresent invention. In the second shaft hole 23 b, a second slidingbearing 22 b is provided. The second sliding bearing 22 b is equivalentto the radial bearing in the present invention. Note that a rollerbearing may be provided instead of the second sliding bearing 22 b.

In the second cylinder block 23, a second recessed portion 23 ccommunicating with the second shaft hole 23 b and coaxial with thesecond shaft hole 23 b is formed. The second recessed portion 23 c alsocommunicates with the swash plate chamber 33 and forms a part of theswash plate chamber 33. Consequently, the second shaft hole 23 bcommunicates with the swash plate chamber 33 on the front end side. Thesecond recessed portion 23 c is formed in a shape reduced in diameterstepwise toward the rear end. A second thrust bearing 35 b is providedat the rear end of the second recessed portion 23 c. Further, in thesecond cylinder block 23, a second communication path 37 b, which allowsthe swash plate chamber 33 and the second suction chamber 27 b tocommunicate with each other, is formed. In the second cylinder block 23,a second retainer groove 23 e, which regulates a maximum opening degreeof second suction reed valves 411 a explained below, is recessed.

In the second cylinder block 23, a discharge port 230, a confluentdelivery chamber 231, a third front side communication path 18 c, asecond rear side communication path 20 b, and a suction port 330 areformed. The discharge port 230 and the confluent delivery chamber 231communicate with each other. The confluent delivery chamber 231 isconnected to a not-shown condenser, which configures a conduit, via thedischarge port 230.

The front end side of the third front side communication path 18 c opensto the front end of the second cylinder block 23. The rear end side ofthe third front side communication path 18 c communicates with theconfluent delivery chamber 231. The first cylinder block 21 and thesecond cylinder block 23 are joined, whereby the third front sidecommunication path 18 c communicates with the rear end side of thesecond front side communication path 18 b.

The front end side of the second rear side communication path 20 bcommunicates with the confluent delivery chamber 231. The rear end sideof the second rear side communication path 20 b opens to the rear end ofthe second cylinder block 23.

The suction port 330 is formed in the second cylinder block 23. Theswash plate chamber 33 is connected to a not-shown evaporator, whichconfigures the conduit, via the suction port 330.

The first valve forming plate 39 is provided between the front housing17 and the first cylinder block 21. The second valve forming plate 41 isprovided between the rear housing 19 and the second cylinder block 23.

The first valve forming plate 39 includes a first valve plate 390, afirst suction valve plate 391, a first discharge valve plate 392, and afirst retainer plate 393. In the first valve plate 390, the firstdischarge valve plate 392, and the first retainer plate 393, firstsuction holes 390 a as many as the first cylinder bores 21 a are formed.In the first valve plate 390 and the first suction valve plate 391,first discharge holes 390 b as many as the first cylinder bores 21 a areformed. Further, in the first valve plate 390, the first suction valveplate 391, the first discharge valve plate 392, and the first retainerplate 393, first suction communication holes 390 c are formed. In thefirst valve plate 390 and the first suction valve plate 391, firstdischarge communication holes 390 d are formed.

The first cylinder bores 21 a communicate with the first suction chamber27 a through the first suction holes 390 a. The first cylinder bores 21a communicate with the first discharge chamber 29 a through the firstdischarge holes 390 b. The first suction chamber 27 a and the firstcommunication path 37 a communicate with each other through the firstsuction communication holes 390 c. A first front side communication path18 a and a second front side communication path 18 b communicate witheach other through the first discharge communication holes 390 d.

The first suction valve plate 391 is provided on the rear surface of thefirst valve plate 390. In the first suction valve plate 391, a pluralityof first suction reed valves 391 a capable of opening and closing thefirst suction holes 390 a through elastic deformation are formed. Thefirst discharge valve plate 392 is provided on the front surface of thefirst valve plate 390. In the first discharge valve plate 392, aplurality of first discharge reed valves 392 a capable of opening andclosing the first discharge holes 390 b through elastic deformation areformed. The first retainer plate 393 is provided on the front surface ofthe first discharge valve plate 392. The first retainer plate 393regulates a maximum opening degree of the first discharge reed valves392 a.

The second valve forming plate 41 includes a second valve plate 410, asecond suction valve plate 411, a second discharge valve plate 412, anda second retainer plate 413. In the second valve plate 410, the seconddischarge valve plate 412, and the second retainer plate 413, secondsuction holes 410 a as many as the second cylinder bores 23 a areformed. In the second valve plate 410 and the second suction valve plate411, second discharge holes 410 b as many as the second cylinder bores23 a are formed. Further, in the second valve plate 410, the secondsuction valve plate 411, the second discharge valve plate 412, and thesecond retainer plate 413, second suction communication holes 410 c areformed. In the second valve plate 410 and the second suction valve plate411, second discharge communication holes 410 d are formed.

The second cylinder bores 23 a communicate with the second suctionchamber 27 b through the second suction holes 410 a. The second cylinderbores 23 a communicate with the second discharge chamber 29 b throughthe second discharge holes 410 b. The second suction chamber 27 b andthe second communication path 37 b communicate with each other throughthe second suction communication holes 410 c. The first rear sidecommunication path 20 a and the second rear side communication path 20 bcommunicate with each other through the second discharge communicationholes 410 d.

The second suction valve plate 411 is provided on the front surface ofthe second valve plate 410. In the second suction valve plate 411, aplurality of second suction reed valves 411 a capable of opening andclosing the second suction holes 410 a through elastic deformation areformed. The second discharge valve plate 412 is provided on the rearsurface of the second valve plate 410. In the second discharge valveplate 412, a plurality of second discharge reed valves 412 a capable ofopening and closing the second discharge holes 410 b through elasticdeformation are formed. The second retainer plate 413 is provided on therear surface of the second discharge valve plate 412. The secondretainer plate 413 regulates a maximum opening degree of the seconddischarge reed valves 412 a.

In the compressor, a first discharge communication path 18 is formed bythe first front side communication path 18 a, the first dischargecommunication holes 390 d, the second front side communication path 18b, and the third front side communication path 18 c. A second dischargecommunication path 20 is formed by the first rear side communicationpath 20 a, the second discharge communication holes 410 d, and thesecond rear side communication path 20 b.

In the compressor, the first and second suction chambers 27 a and 27 band the swash plate chamber 33 communicate with each other through thefirst and second communication paths 37 a and 37 b and the first andsecond suction communication holes 390 c and 410 c. Therefore, pressuresin the first and second suction chambers 27 a and 27 b and in the swashplate chamber 33 are substantially equal. A low-pressure refrigerant gaspassed through the evaporator flows into the swash plate chamber 33through the suction port 330. Therefore, the pressures in the swashplate chamber 33 and in the first and second suction chambers 27 a and27 b are lower than pressure in the first and second discharge chambers29 a and 29 b.

The drive shaft 3 is configured by a drive shaft main body 30, a firstsupporting member 43 a, and a second supporting member 43 b. The driveshaft main body 30 extends from the front side to the rear side of thehousing 1. The drive shaft main body 30 is inserted rearward from theboss 17 a and inserted through the first and second sliding bearings 22a and 22 b. Consequently, the drive shaft main body 30, and byextension, the drive shaft 3 are axially supported by the housing 1 tobe rotatable around a rotational axis O. The front end of the driveshaft main body 30 is located in the boss 17 a. The rear end of thedrive shaft main body 30 projects into the pressure regulation chamber31.

In the drive shaft main body 30, the swash plate 5, the link mechanism7, and the actuator 13 are provided. The swash plate 5, the linkmechanism 7, and the actuator 13 are respectively arranged in the swashplate chamber 33.

The first supporting member 43 a is pressed into the front end side ofthe drive shaft main body 30 and located between the drive shaft mainbody 30 and the first sliding bearing 22 a in the first shaft hole 21 b.In the first supporting member 43 a, a flange 430, which comes intocontact with the first thrust bearing 35 a, is formed and an attachingportion (not shown in the figure), through which a second pin 47 bexplained below is inserted, is formed. Further, the front end of afirst return spring 44 a is fixed to the first supporting member 43 a.The first return spring 44 a extends from the first supporting member 43a side to the swash plate chamber 33 side in the rotational axis Odirection.

As shown in FIG. 3, the second supporting member 43 b is pressed intothe rear end side of the drive shaft main body 30 and located betweenthe drive shaft main body 30 and the second sliding bearing 22 b in thesecond shaft hole 23 b. The second supporting member 43 b is equivalentto the cap in the present invention. A flange 431 is formed at the frontend of the second supporting member 43 b. The flange 431 projects intothe second recessed portion 23 c and is in contact with the secondthrust bearing 35 b. In the second supporting member 43 b, a reduceddiameter portion 432 is formed on the rear end side. The rear end of thereduced diameter portion 432 projects into the pressure regulationchamber 31.

Further, in the second supporting member 43 b, first and second recessedstrip portions 433 and 434 concentric with the rotational axis O arerecessed in a position between the flange 431 and the reduced diameterportion 432. The first and second recessed strip portions 433 and 434allow the pressure regulation chamber 31 and the swash plate chamber 33to communicate with each other via the second sliding bearing 22 b. Afirst annular member 61 a is accommodated in the first recessed stripportion 433. A second annular member 61 b is housed in the secondrecessed strip portion 434. Consequently, the first and second annularmembers 61 a and 61 b are located between the second supporting member43 b and the second shaft hole 23 b.

The second sliding bearing 22 b is pressed into the reduced diameterportion 432. In this way, the second sliding bearing 22 b is provided inthe second shaft hole 23 b and located on the rear end side of thesecond shaft hole 23 b. Since the second sliding bearing 22 b is locatedon the rear end side of the second shaft hole 23 b, in the compressor,the second sliding bearing 22 b is arranged further on the pressureregulation chamber 31 side than the first and second annular members 61a and 61 b in the second shaft hole 23 b. The rear end of the secondsliding bearing 22 b faces the pressure regulation chamber 31.

The outer diameter of the first annular member 61 a, the outer diameterof the second annular member 61 b, and the outer diameter of the secondsliding bearing 22 b are formed substantially the same. Consequently, inthe compressor, all of the outer circumferential surface of the firstannular member 61 a, the outer circumferential surface of the secondannular member 61 b, and the outer circumferential surface of the secondsliding bearing 22 b are capable of coming into slide contact with theinner circumferential surface of the second shaft hole 23 b.

Both the first and second annular members 61 a and 61 b are made ofPEEK. The first and second annular members 61 a and 61 b have the sameconfiguration. As shown in FIG. 4A, the first and second annular members61 a and 61 b respectively include joint gap 63. The configuration isexplained below with reference to the joint gap 63 of the first annularmember 61 a as an example.

As shown in FIG. 4B, the joint gap 63 is formed by first to thirdcutouts 630 a to 630 c. The first cutout 630 a extends in the axialdirection of the first annular member 61 a. The second cutout 630 bextends in the axial direction of the first annular member 61 a whileshifting in the circumferential direction with respect to the firstcutout 630 a. The third cutout 630 c extends in the circumferentialdirection in the center in the thickness direction of the first annularmember 61 a and is continuous to the first cutout 630 a and the secondcutout 630 b. The joint gap 63 is formed in a crank shape by the firstto third cutouts 630 a to 630 c. As shown in FIGS. 5A and 5B, theannular members 61 a and 61 b are respectively provided in the first andsecond recessed strip portions 433 and 434, whereby the third cutout 630c allows the pressure regulation chamber 31 and the swash plate chamber33 to always communicate with each other. Therefore, as indicated bysolid line arrows in the figure, lubricant included in the refrigerantcan circulate through the third cutout 630 c together with therefrigerant.

As shown in FIG. 4C, in the joint gap 63, the third cutout 630 c isformed to have a small channel area for the refrigerant and the likecompared with the first and second cutouts 630 a and 630 b.Consequently, the third cutout 630 c functions as an aperture in thefirst and second annular members 61 a and 61 b. A portion between thesecond shaft hole 23 b and the second supporting member 43 b, the firstand second recessed strip portions 433 and 434, and the third cutouts630 c function as the communication path in the present invention. Notethat the annular members 61 a and 61 b may be formed by metal or thelike.

As shown in FIG. 3, in the compressor, the second shaft hole 23 b andthe pressure regulation chamber 31 are defined by the first and secondannular members 61 a and 61 b. As explained above, the joint gap 63 arerespectively formed in the first and second annular members 61 a and 61b. Therefore, it is possible to allow the second shaft hole 23 b and thepressure regulation chamber 31 to communicate with each other throughthe joint gap 63.

As shown in FIG. 1, the swash plate 5 is formed in an annular flat plateshape and includes a front surface 5 a and a rear surface 5 b. The frontsurface 5 a faces the front of the compressor in the swash plate chamber33. The rear surface 5 b faces the rear of the compressor in the swashplate chamber 33.

The swash plate 5 is fixed to a ring plate 45. The ring plate 45 isformed in an annular flat plate shape. An insertion hole 45 a is formedin a center portion of the ring plate 45. The drive shaft main body 30is inserted through the insertion hole 45 a in the swash plate chamber33, whereby the swash plate 5 is attached to the drive shaft 3.

The link mechanism 7 includes a lug arm 49. The lug arm 49 is arrangedfurther in the front than the swash plate 5 in the swash plate chamber33 and located between the swash plate 5 and the first supporting member43 a. The lug arm 49 is formed to have a substantially L shape from thefront end side to the rear end side. As shown in FIG. 6, the lug arm 49comes into contact with the flange 430 of the first supporting member 43a when an inclination angle of the swash plate 5 with respect to therotational axis O is the smallest. A weight portion 49 a is formed onthe rear end side of the lug arm 49. The weight portion 49 a extends inthe circumferential direction of the actuator 13 over a halfcircumference thereof. Note that the shape of the weight portion 49 acan be designed as appropriate.

As shown in FIG. 1, the rear end side of the lug arm 49 is connected toone end side of the ring plate 45 by a first pin 47 a. Consequently,with the axis of the first pin 47 a set as a first pivot axis M1, thefront end side of the lug arm 49 is pivotably supported around the firstpivot axis M1 with respect to one end side of the ring plate 45, thatis, the swash plate 5. The first pivot axis M1 extends in a directionorthogonal to the rotational axis O of the drive shaft 3.

The front end side of the lug arm 49 is connected to the firstsupporting member 43 a by a second pin 47 b. Consequently, with the axisof the second pin 47 b set as a second pivot axis M2, the rear end sideof the lug arm 49 is pivotably supported around the second pivot axis M2with respect to the first supporting member 43 a, that is, the driveshaft 3. The second pivot axis M2 extends in parallel to the first pivotaxis M1. The lug arm 49 and the first and second pins 47 a and 47 b areequivalent to the link mechanism 7 in the present invention.

The weight portion 49 a is provided to extend to the rear end side ofthe lug arm 49, that is, the opposite side of the second pivot axis M2with respect to the first pivot axis M1. Therefore, the lug arm 49 issupported on the ring plate 45 by the first pin 47 a, whereby the weightportion 49 a is located on the rear surface of the ring plate 45, thatis, the rear surface 5 b side of the swash plate 5 through a grooveportion 45 b of the ring plate 45. A centrifugal force generated by therotation of the swash plate 5 around the rotational axis O acts on theweight portion 49 a on the rear surface 5 b side of the swash plate 5.

In the compressor, the swash plate 5 and the drive shaft 3 are connectedby the link mechanism 7, whereby the swash plate 5 is capable ofrotating together with the drive shaft 3. Both ends of the lug arm 49respectively pivot around the first pivot axis M1 and the second pivotaxis M2, whereby the swash plate 5 is capable of changing theinclination angle.

The pistons 9 respectively include first head portions 9 a on the frontend side and include second head portions 9 b on the rear end side. Thefirst head portions 9 a are accommodated to be reciprocatingly movablein the first cylinder bores 21 a. First compression chambers 21 d arerespectively defined in the first cylinder bores 21 a by the first headportions 9 a and the first valve forming plate 39. The second headportions 9 b are accommodated to be reciprocatingly movable in thesecond cylinder bores 23 a. Second compression chambers 23 d arerespectively defined in the second cylinder bores 23 a by the secondhead portions 9 b and the second valve forming plate 41.

Engaging portions 9 c are formed in the centers of the pistons 9.Semispherical shoes 11 a and 11 b are respectively provided in theengaging portions 9 c. The rotation of the swash plate 5 is convertedinto reciprocating movement of the pistons 9 by the shoes 11 a and 11 b.The shoes 11 a and 11 b are equivalent to the conversion mechanism inthe present invention. Consequently, the first and second head portions9 a and 9 b are respectively capable of reciprocatingly moving in thefirst and second cylinder bores 21 a and 23 a at a stroke correspondingto the inclination angle of the swash plate 5.

Here, in the compressor, a stroke of the pistons 9 changes according toa change in the inclination angle of the swash plate 5, whereby top deadcenter positions of the first head portion 9 a and the second headportion 9 b move. Specifically, as the inclination angle of the swashplate 5 decreases, the top dead center position of the second headportion 9 b more largely moves than the top dead center position of thefirst head portion 9 a.

As shown in FIG. 1, the actuator 13 is arranged in the swash platechamber 33. The actuator 13 is located further on the rear side than theswash plate 5 and is capable of entering the second recessed portion 23c. The actuator 13 includes a movable body 13 a, a fixed body 13 b, anda control pressure chamber 13 c. The control pressure chamber 13 c isformed between the movable body 13 a and the fixed body 13 b.

The movable body 13 a includes a main body portion 130 and acircumferential wall 131. The main body portion 130 is located in therear of the movable body 13 a and extends in the radial direction in adirection away from the rotational axis O. The circumferential wall 131is continuous to the outer circumferential edge of the main body portion130 and extends from the front to the rear. A coupling portion 132 isformed at the front end of the circumferential wall 131. The movablebody 13 a is formed in a bottomed cylindrical shape by the main bodyportion 130, the circumferential wall 131, and the coupling portion 132.

The fixed body 13 b is formed in a disk shape having a diametersubstantially the same as the inner diameter of the movable body 13 a. Asecond return spring 44 b is provided between the fixed body 13 b andthe ring plate 45. Specifically, the rear end of the second returnspring 44 b is fixed to the fixed body 13 b. The front end of the secondreturn spring 44 b is fixed to the other end side of the ring plate 45.

The drive shaft main body 30 is inserted through the movable body 13 aand the fixed body 13 b. Consequently, in a state in which the movablebody 13 a is accommodated in the second recessed portion 23 c, themovable body 13 a is arranged to be opposed to the link mechanism 7across the swash plate 5. On the other hand, the fixed body 13 b isarranged in the movable body 13 a further in the rear than the swashplate 5 and is surrounded by the circumferential wall 131. Consequently,the control pressure chamber 13 c is formed a space between the movablebody 13 a and the fixed body 13 b. The control pressure chamber 13 c ispartitioned from the swash plate chamber 33 by the main body portion 130and the circumferential wall 131 of the movable body 13 a and the fixedbody 13 b.

In the compressor, since the drive shaft main body 30 is insertedthrough the movable body 13 a, the movable body 13 a is rotatabletogether with the drive shaft 3 and is capable of moving in therotational axis O direction of the drive shaft 3 in the swash platechamber 33. On the other hand, the fixed body 13 b is fixed to the driveshaft main body 30 in a state in which the fixed body 13 b is insertedthrough the drive shaft main body 30. Consequently, the fixed body 13 bis capable of only rotating together with the drive shaft 3 and isincapable of moving like the movable body 13 a. In this way, in movingin the rotational axis O direction, the movable body 13 a relativelymoves with respect to the fixed body 13 b.

The other end side of the ring plate 45 is connected to the couplingportion 132 of the movable body 13 a by a third pin 47 c. Consequently,with the axis of the third pin 47 c set as an action axis M3, the otherend side of the ring plate 45, that is, the swash plate 5 is pivotablysupported by the movable body 13 a around the action axis M3. The actionaxis M3 extends in parallel to the first and second pivot axes M1 andM2. In this way, the movable body 13 a is coupled to the swash plate 5.The movable body 13 a comes into contact with the flange 431 of thesecond supporting member 43 b when the inclination angle of the swashplate 5 is the largest.

In the drive shaft main body 30, an axial path 3 a extending in therotational axis O direction from the rear end to the front and a radialpath 3 b extending in the radial direction from the front end of theaxial path 3 a and opening to the outer circumferential surface of thedrive shaft main body 30 are formed. The rear end of the axial path 3 aopens to the pressure regulation chamber 31. On the other hand, theradial path 3 b opens to the control pressure chamber 13 c.Consequently, the control pressure chamber 13 c communicates with thepressure regulation chamber 31 through the radial path 3 b and the axialpath 3 a.

A screw portion 3 d is formed at the tip end of the drive shaft mainbody 30. The drive shaft 3 is connected to a not-shown pulley orelectromagnetic clutch via the screw portion 3 d.

As shown in FIG. 2, the control mechanism 15 includes a low pressurepassage 15 a, a high pressure passage 15 b, a control valve 15 c, anorifice 15 d, the axial path 3 a, and the radial path 3 b.

The low pressure passage 15 a is connected to the pressure regulationchamber 31 and the second suction chamber 27 b. The control pressurechamber 13 c, the pressure regulation chamber 31, and the second suctionchamber 27 b communicate with one another through the low pressurepassage 15 a, the axial path 3 a, and the radial path 3 b. The highpressure passage 15 b is connected to the pressure regulation chamber 31and the second discharge chamber 29 b. The control pressure chamber 13c, the pressure regulation chamber 31, and the second discharge chamber29 b communicate with one another through the high pressure passage 15b, the axial path 3 a, and the radial path 3 b. The orifice 15 d isprovided in the high pressure passage 15 b.

The control valve 15 c is provided in the low pressure passage 15 a. Thecontrol valve 15 c is capable of adjusting an opening degree of the lowpressure passage 15 a on the basis of the pressure in the second suctionchamber 27 b.

In the compressor, a pipe joined to the evaporator is connected to thesuction port 330 shown in FIG. 1. A pipe joined to the condenser isconnected to the discharge port 230. The condenser is connected to theevaporator via a pipe and an expansion valve. A refrigerant circuit ofan air-conditioning apparatus for a vehicle is configured by thecompressor, the evaporator, the expansion valve, the condenser, and thelike. Note that illustration of the evaporator, the expansion valve, thecondenser, and the pipes are omitted in the figure.

In the compressor configured as explained above, the drive shaft 3rotates, whereby the swash plate 5 rotates and the pistons 9reciprocatingly move in the first and second cylinder bores 21 a and 23a. Therefore, the first and second compression chambers 21 d and 23 dcause a capacity change according to a piston stroke. Therefore, in thecompressor, a suction stroke for sucking a refrigerant gas into thefirst and second compression chambers 21 d and 23 d, a compressionstroke in which the refrigerant gas is compressed in the first andsecond compression chambers 21 d and 23 d, a discharge stroke in whichthe compressed refrigerant gas is discharged to the first and seconddischarge chambers 29 a and 29 b, and the like are repeatedly performed.

The refrigerant gas discharged to the first discharge chamber 29 areaches the confluent delivery chamber 231 through the first dischargecommunication path 18. Similarly, the refrigerant gas discharged to thesecond discharge chamber 29 b reaches the confluent delivery chamber 231through the second discharge communication path 20. The refrigerant gasreached the confluent delivery chamber 231 is discharged to thecondenser from the discharge port 230.

When the suction stroke and the like are performed, a piston compressionforce for reducing the inclination angle of the swash plate 5 acts on arotating body formed by the swash plate 5, the ring plate 45, the lugarm 49, and the first pin 47 a. If the inclination angle of the swashplate 5 is changed, it is possible to perform capacity control by anincrease and a decrease of the stroke of the piston 9.

Specifically, in the control mechanism 15, if the control valve 15 cshown in FIG. 2 increases the opening degree of the low pressure passage15 a, the pressure in the pressure regulation chamber 31, and byextension, in the control pressure chamber 13 c are substantially equalto the pressure in the second suction chamber 27 b. Therefore, with thepiston compression force acting on the swash plate 5, as shown in FIG.6, in the actuator 13, the movable body 13 a moves to the front side ofthe swash plate chamber 33. Therefore, in the compressor, the movablebody 13 a approaches the lug arm 49 and the capacity of the controlpressure chamber 13 c decreases.

Consequently, the other end side of the ring plate 45, that is, theother end side of the swash plate 5 pivots in the clockwise directionaround the action axis M3 while resisting an urging force of the secondreturn spring 44 b. The rear end of the lug arm 49 pivots in theclockwise direction around the first pivot axis M1 and the front end ofthe lug arm 49 pivots in the counterclockwise direction around thesecond pivot axis M2. Therefore, the lug arm 49 approaches the flange430 of the first supporting member 43 a. Consequently, the swash plate 5pivots with the action axis M3 set as a point of action and with thefirst pivot axis M1 set as a fulcrum. Therefore, the inclination angleof the swash plate 5 with respect to the rotational axis O of the driveshaft 3 decreases and the stroke of the piston 9 decreases. Therefore,in the compressor, a discharge capacity per one rotation of the driveshaft 3 decreases. Note that the inclination angle of the swash plate 5shown in FIG. 6 is a minimum inclination angle in the compressor.

In the compressor, the centrifugal force acting on the weight portion 49a is also applied to the swash plate 5. Therefore, in the compressor,the swash plate 5 is easily displaced in a direction for reducing theinclination angle.

The inclination angle of the swash plate 5 decreases, whereby the ringplate 45 comes into contact with the rear end of the first return spring44 a. Consequently, the first return spring 44 a is elastically deformedand the rear end of the first return spring 44 a approaches the firstsupporting member 43 a.

Here, in the compressor, the inclination angle of the swash plate 5decreases and the stroke of the piston 9 decreases, whereby the top deadcenter position of the second head portion 9 b moves away from thesecond valve forming plate 41. Therefore, in the compressor, when theinclination angle of the swash plate 5 approaches a zero degree,compression work is slightly performed on the first compression chamber21 d side. On the other hand, compression work is not performed on thesecond compression chamber 23 d side.

On the other hand, if the control valve 15 c shown in FIG. 2 reduces theopening degree of the low pressure passage 15 a, the pressure in thepressure regulation chamber 31 increases and the pressure in the controlpressure chamber 13 c increases. Therefore, in the actuator 13, as shownin FIG. 1, the movable body 13 a moves toward the rear end side of theswash plate chamber 33 while resisting the piston compression forceacting on the swash plate 5. Therefore, in the compressor, the movablebody 13 a moves away from the lug arm 49 and the capacity of the controlpressure chamber 13 c increases.

Consequently, in the action axis M3, the movable body 13 a tows thelower end side of the swash plate 5 to the rear side of the swash platechamber 33 through the coupling portion 132. Consequently, the other endside of the swash plate 5 pivots in the counterclockwise directionaround the action axis M3. The rear end of the lug arm 49 pivots in thecounterclockwise direction around the first pivot axis M1 and the frontend of the lug arm 49 pivots in the clockwise direction around thesecond pivot axis M2. Therefore, the lug arm 49 separates from theflange 430 of the first supporting member 43 a. Consequently, with theaction axis M3 and the first pivot axis M1 respectively set as a pointof action and a fulcrum, the swash plate 5 pivots in an oppositedirection of the direction in which the inclination angle decreases.Therefore, the inclination angle of the swash plate 5 with respect tothe rotational axis O of the drive shaft 3 increases and the stroke ofthe piston 9 increases. Consequently, the discharge capacity per onerotation of the drive shaft 3 increases. Note that the inclination angleof the swash plate 5 shown in FIG. 1 is a maximum inclination angle inthe compressor.

In the compressor, the pressure regulation chamber 31 is formed in therear housing 19. The control mechanism. 15 allows the second dischargechamber 29 b and the pressure regulation chamber 31 to communicate witheach other through the high pressure passage 15 b and allows the secondsuction chamber 27 b and the pressure regulation chamber 31 tocommunicate with each other through the low pressure passage 15 a.Consequently, in the compressor, the lubricant included in therefrigerant in the second discharge chamber 29 b and the second suctionchamber 27 b is stored in the pressure regulation chamber 31. Asindicated by the solid line arrows in FIG. 5A and FIG. 5B, in thecompressor, with a pressure difference between the pressure regulationchamber 31 and the second recessed portion 23 c, and by extension,between the pressure regulation chamber 31 and the swash plate chamber33, the refrigerant in the pressure regulation chamber 31 circulates tothe swash plate chamber 33 through, besides the third cutouts 630 c ofthe first and second annular members 61 a and 61 b, a gap between thefirst annular member 61 a and the first recessed strip portion 433, agap between the second annular member 61 b and the second recessed stripportion 434, and the like.

In the compressor, the first annular member 61 a moves in the firstrecessed strip portion 433 and the second annular member 61 b moves inthe second recessed strip portion 434 on the basis of the pressuredifference between the pressure regulation chamber 31 and the swashplate chamber 33. Consequently, in the compressor, it is possible toadjust flow rates of the refrigerant circulating through the gap betweenthe first annular member 61 a and the first recessed strip portion 433and the gap between the second annular member 61 b and the secondrecessed strip portion 434, that is, a flow rate of the refrigerantcirculating from the pressure regulation chamber 31 to the swash platechamber 33.

Specifically, as explained above, if the pressure in the pressureregulation chamber 31 is increased to increase the pressure differencebetween the pressure regulation chamber 31 and the swash plate chamber33, as shown in FIG. 5A, the first and second annular members 61 a and61 b respectively move forward in the first and second recessed stripportions 433 and 434. Consequently, the first annular member 61 a comesinto contact with the front wall surface of the first recessed stripportion 433. In this contact place, the gap between the first annularmember 61 a and the first recessed strip portion 433 is closed.Similarly, the second annular member 61 b comes into contact with thefront wall surface of the second recessed strip portion 434. In thiscontact place, the gap between the second annular member 61 b and thesecond recessed strip portion 434 is closed. Consequently, as indicatedby the solid line arrows in the figure, the refrigerant in the pressureregulation chamber 31 circulates only through the third cutouts 630 c ofthe first and second annular members 61 a and 61 b and circulate to theswash plate chamber 33. Therefore, the flow rate of the refrigerantcirculating from the pressure regulation chamber 31 to the swash platechamber 33 decreases.

On the other hand, as explained above, if the pressure in the pressureregulation chamber 31 is reduced and the pressure difference between thepressure regulation chamber 31 and the swash plate chamber 33 isreduced, as shown in FIG. 5B, the first and second annular members 61 aand 61 b respectively move to substantially the centers in the first andsecond recessed strip portions 433 and 434. Therefore, as indicated bythe solid line arrows in the figure, the refrigerant in the pressureregulation chamber 31 circulates through the third cutouts 630 c of thefirst and second annular members 61 a and 61 b, the gap between thefirst annular member 61 a and the first recessed strip portion 433, andthe gap between the second annular member 61 b and the second recessedstrip portion 434 and circulates to the swash plate chamber 33. That is,compared with a state in which the pressure difference between thepressure regulation chamber 31 and the swash plate chamber 33 is largeshown in FIG. 5A, the flow rate of the refrigerant circulating from thepressure regulation chamber 31 to the swash plate chamber 33 increases.

When the refrigerant circulates through the third cutouts 630 c and thelike in this way, in the compressor, the lubricant stored in thepressure regulation chamber 31 also circulates through the third cutouts630 c and the like together with the refrigerant. Consequently, in thecompressor, it is possible to supply the lubricant to the second slidingbearing 22 b provided in the second shaft hole 23 b. Therefore, in thecompressor, it is possible to suitably lubricate a portion between thesecond sliding bearing 22 b and the second supporting member 43 b withthe supplied lubricant. In this case, in the compressor, as explainedabove, the first and second annular members 61 a and 61 b adjust theflow rates of the refrigerant circulating through the gap between thefirst annular member 61 a and the first recessed strip portion 433 andthe gap between the second annular member 61 b and the second recessedstrip portion 434. Accordingly, a supply amount of the lubricantsupplied to the second sliding bearing 22 b is also adjusted. Therefore,in the compressor, seizure less easily occurs between the secondsupporting member 43 b and the second sliding bearing 22 b.

Therefore, the compressor in embodiment 1 displays high durability inthe compressor that changes a discharge capacity using the actuator 13.

In particular, in the compressor, the first and second annular members61 a and 61 b respectively adjust the flow rates of the refrigerantflowing through the gap between the first annular member 61 a and thefirst recessed strip portion 433 and the gap between the second annularmember 61 b and the second recessed strip portion 434. Consequently, inthe compressor, it is possible to regulate the pressure in the pressureregulation chamber 31 while preventing the refrigerant from circulatingfrom the pressure regulation chamber 31 to the swash plate chamber 33more than necessary through the gaps and the third cutouts 630 c.Therefore, in the compressor, it is easy to change the pressure in thecontrol pressure chamber 13 c with the pressure of the refrigerant inthe second discharge chamber 29 b. It is possible to suitably change thedischarge capacity.

As explained above, in the compressor, the first annular member 61 aadjusts the flow rate of the refrigerant circulating through the gapbetween the first annular member 61 a and the first recessed stripportion 433 and the second annular member 61 b adjusts the flow rate ofthe refrigerant circulating through the gap between the second annularmember 61 b and the second recessed strip portion 434. Consequently, inthe compressor, the first and second annular members 61 a and 61 bfunction as valves that regulate the pressure in the pressure regulationchamber 31. Further, the first and second annular members 61 a and 61 balso function as valves that adjust the supply amount of the lubricantsupplied to the second sliding bearing 22 b. In general, since suchvalves have a complicated configuration and a large size, it isdifficult to arrange the valves around the drive shaft 3. On the otherhand, in the compressor, a configuration is simple in which the firstand second annular members 61 a and 61 b respectively include the jointgap 63 including the third cutouts 630 c functioning as aperture.Therefore, in the compressor, it is possible to cause the first andsecond annular members 61 a and 61 b to function as the valves asexplained above while arranging the first and second annular members 61a and 61 b around the second supporting member 43 b.

In the compressor, the joint gap 63 of the first and second annularmembers 61 a and 61 b are configured by the first to third cutouts 630 ato 630 c. As explained above, the third cutouts 630 c function as theaperture in the first and second annular members 61 a and 61 b. Here,when the first and second annular members 61 a and 61 b are respectivelyassembled to the first and second recessed strip portions 433 and 434 ofthe second supporting member 43 b, in the first and second cutouts 630 aand 630 b extending in the axial direction, the width, that is, achannel area in the circulation of the refrigerant and the lubricanteasily changes because of tolerance and the like during the assemblingbesides tolerance of the diameters of the second supporting member 43 band the first and second recessed strip portions 433 and 434. On theother hand, in the third cutouts 630 c extending in the circumferentialdirection, a channel area less easily changes even when the first andsecond annular members 61 a and 61 b are assembled to the secondsupporting member 43 b. Therefore, in the compressor, it is possible tosuitably adjust the flow rate of the refrigerant circulating from thepressure regulation chamber 31 to the swash plate chamber 33. It is alsopossible to suitably adjust the supply amount of the lubricant suppliedto the second sliding bearing 22 b and the like.

Further, in the compressor, since the first and second annular members61 a and 61 b are made of PEEK, friction and the like are less easilycaused even by a load and oil resistance is high. The first and secondannular members 61 a and 61 b are also excellent in affinity to thelubricant.

Further, in the compressor, since the first annular member 61 a and thesecond annular member 61 b are provided in the second supporting member43 b, the first and second annular members 61 a and 61 b are capable ofadjusting a load that acts during actuation of the compressor.Consequently, in the compressor, durability of the first and secondannular members 61 a and 61 b is high.

In the compressor, the outer diameters of the first and second annularmembers 61 a and 61 b and the outer diameters of the second slidingbearing 22 b are formed substantially the same. Therefore, in thecompressor, the first and second annular members 61 a and 61 b suitablycome into slide contact with the inner circumferential surface of thesecond shaft hole 23 b and the second sliding bearing 22 b suitablycomes into slide contact with the inner circumferential surface of thesecond shaft hole 23 b. Consequently, in the compressor, both of thefirst and second annular members 61 a and 61 b and the second slidingbearing 22 b suitably function.

Further, in the compressor, in the second shaft hole 23 b, the secondsliding bearing 22 b is arranged further on the pressure regulationchamber 31 side than the first and second annular members 61 a and 61 b.The rear end of the second sliding bearing 22 b faces the pressureregulation chamber 31. Consequently, in the compressor, it is possibleto suitably lubricate the second sliding bearing 22 b with the lubricantin the pressure regulation chamber 31.

In the compressor, the drive shaft 3 is configured by the drive shaftmain body 30 and first and second supporting members 43 a and 43 b.Therefore, in the compressor, it is possible to suppress complication ofthe shape of the drive shaft main body 30 and easily manufacture thedrive shaft 3. Since the first and second annular members 61 a and 61 bare provided in the second supporting member 43 b, it is easy to providethe first and second annular members 61 a and 61 b in the drive shaft 3.

Embodiment 2

In a compressor in embodiment 2, a second supporting member 46 shown inFIG. 7 is pressed into the drive shaft main body 30 instead of thesecond supporting member 43 b in the compressor in embodiment 1.Consequently, in the compressor, the drive shaft 3 is configured by thedrive shaft main body 30, the first supporting member 43 a, and thesecond supporting member 46.

In the compressor, a second sliding bearing 22 c is provided in thesecond shaft hole 23 b instead of the second sliding bearing 22 b. Thesecond sliding bearing 22 c is also equivalent to the radial bearing inthe present invention. Note that a roller bearing may be providedinstead of the second sliding bearing 22 c.

The second supporting member 46 is pressed into the rear end side of thedrive shaft main body 30 and located in the second shaft hole 23 b. Thesecond supporting member 46 is also equivalent to the cap in the presentinvention. A flange 461 is formed at the front end of the secondsupporting member 46. The flange 461 projects into the second recessedportion 23 c and is in contact with the second thrust bearing 35 b. Themovable body 13 a comes into contact with the flange 461 when theinclination angle of the swash plate 5 is the largest.

A reduced diameter portion 462 is formed on the rear end side of thesecond supporting member 46. In the reduced diameter portion 462, firstand second recessed strip portions 463 and 464 concentric with therotational axis O are recessed. In the first recessed strip portion 463,as in the compressor in embodiment 1, the first annular member 61 a isarranged. In the second recessed strip portion 464, the second annularmember 61 b is arranged. Consequently, the first and second annularmembers 61 a and 61 b are located between the second supporting member46 and the second shaft hole 23 b. The rear end of the second supportingmember 46, that is, the reduced diameter portion 462 projects into thepressure regulation chamber 31.

The second sliding bearing 22 c is located on the front end side of thesecond shaft hole 23 b. The inner diameter of the second sliding bearing22 c is formed substantially the same as the outer diameter of the firstannular member 61 a and the outer diameter of the second annular member61 b. In the compressor, as explained above, the first and secondannular members 61 a and 61 b are provided in the first and secondrecessed strip portions 463 and 464 and located on the rear end side ofthe second supporting member 46. Consequently, in the compressor, in thesecond shaft hole 23 b, the first and second annular members 61 a and 61b are arranged further on the pressure regulation chamber 31 side thanthe second sliding bearing 22 c. A portion between the second shaft hole23 b and the second supporting member 46, the first and second recessedstrip portions 463 and 464, and the third cutouts 630 c function as thecommunication path in the present invention. The other components in thecompressor are the same as the components in the compressor inembodiment 1. The same components are denoted by the same referencenumerals and signs and detailed explanation concerning the components isomitted.

In the compressor, as explained above, the first and second annularmembers 61 a and 61 b are arranged further on the pressure regulationchamber 31 side than the second sliding bearing 22 c. In this regard, inthe compressor, as in the compressor in embodiment 1, the refrigerantand the lubricant circulate through, besides the third cutouts 630 c,the gap between the first annular member 61 a and the first recessedstrip portion 463, the gap between the second annular member 61 b andthe second recessed strip portion 464, and the like. Therefore, thesecond sliding bearing 22 c and the like are suitably lubricated.Therefore, in the compressor, as in the compressor in embodiment 1,seizure less easily occurs between the second supporting member 46 andthe second sliding bearing 22 c.

In the compressor, the outer diameters of the first and second annularmembers 61 a and the inner diameter of the second sliding bearing 22 care formed substantially the same. Therefore, in the compressor, thefirst and second annular members 61 a and 61 b suitably come into slidecontact with the inner circumferential surface of the second shaft hole23 b and the second supporting member 46 and the inner circumferentialsurface of the second sliding bearing 22 c suitably come into slidecontact with each other. Therefore, in the compressor, as in thecompressor in embodiment 1, both of the first and second annular members61 a and 61 b and the second sliding bearing 22 c suitably function. Theother action in the compressor is the same as the action in thecompressor in embodiment 1.

Embodiment 3

In a compressor in embodiment 3, first and second annular members 65 aand 65 b shown in FIG. 8A are adopted instead of the first and secondannular members 61 a and 61 b in the compressor in embodiment 1. Thefirst and second annular members 65 a and 65 b are also made of PEEK.The first and second annular members 65 a and 65 b are also respectivelyaccommodated in the first and second recessed strip portions 433 and 434and located between the second supporting member 43 b and the secondshaft hole 23 b.

The first and second annular members 65 a and 65 b have the sameconfiguration and respectively include joint gap 67. The configurationis explained below with reference to the joint gap 67 of the firstannular member 65 a as an example.

As shown in FIGS. 8A and 8B, the joint gap 67 is formed by first tothird cutouts 670 a to 670 c and a pair of communication grooves 670 dand 670 e. The first cutout 670 a extends in the axial direction of thefirst annular member 65 a. The second cutout 670 b extends in the axialdirection of the first annular member 65 a while shifting in thecircumferential direction with respect to the first cutout 670 a. Thethird cutout 670 c extends in the circumferential direction in thecenter of the thickness direction of the first annular member 65 a andis continuous to the first cutout 670 a and the second cutout 670 b. Asshown in FIG. 8C, the communication grooves 670 d and 670 e are formedin a substantially semicircular shape in a cross section parallel to theaxial direction. The communication grooves 670 d and 670 e extend alongthe third cutout 670 c while being opposed to each other across thethird cutout 670 c and are respectively continuous to the first cutout670 a and the second cutout 670 b.

The first and second annular members 65 a and 65 b are respectivelyprovided in the first and second recessed strip portions 433 and 434,whereby the third cutout 670 c allows the pressure regulation chamber 31and the swash plate chamber 33 to always communicate with each other.Like the first and second annular members 61 a and 61 b, the thirdcutout 670 c is formed to have a small channel area for the refrigerantand the like compared with the first and second cutouts 670 a and 670 b.Consequently, the third cutout 670 c functions as an aperture in thefirst and second annular members 65 a and 65 b. The portion between thesecond shaft hole 23 b and the second supporting member 43 b, the firstand second recessed strip portions 433 and 434, and the third cutouts670 c function as the communication path in the present invention. Notethat the annular members 65 a and 65 b may be formed by metal or thelike. The other components in the compressor are the same as thecomponents in the compressor in embodiment 1.

The first and second annular members 65 a and 65 b act the same as thefirst and second annular members 61 a and 61 b in the compressor inembodiment 1. Here, in the first and second annular members 65 a and 65b, flow rates of the refrigerant and the lubricant can also be adjustedby the communication grooves 670 d and 670 e. The other action in thecompressor is the same as the action in the compressor in embodiment 1.

The present invention is explained above according to embodiments 1 to3. However, the present invention is not limited to embodiments 1 to 3.It goes without saying that the present invention can be changed asappropriate and applied without departing from the spirit of the presentinvention.

For example, in the compressor in embodiment 1, only the first annularmember 61 a may be provided in the second supporting member 43 b. Threeor more annular members may be provided in the second supporting member43 b. The same applies to the compressors in embodiments 2 and 3.

The first and second annular members 65 a and 65 b in the compressor inembodiment 3 may be provided in the compressor in embodiment 2.

Further, concerning the control mechanism 15, the control valve 15 c maybe provided in the high pressure passage 15 b and the orifice 15 d maybe provided in the low pressure passage 15 a. In this case, it ispossible to adjust the opening degree of the high pressure passage 15 bwith the control valve 15 c. Consequently, it is possible to quicklyincrease the pressure in the control pressure chamber 13 c with the highpressure in the second discharge chamber 29 b and quickly increase acompression capacity.

The compressor may be configured such that a compression chamber isformed only in one of the first cylinder block 21 and the secondcylinder block 23.

The annular member is preferably formed by resin such as PEEK (polyetherether ketone), PPS (polyphenylene sulfide), or PTFE(polytetrafluoroethylene) or metal. On the other hand, for example, amember that seals the communication path and blocks circulation of therefrigerant and the lubricant like an O-ring made of rubber is notincluded in the annular member in the present invention.

1. A variable displacement swash plate type compressor comprising: ahousing in which a suction chamber, a discharge chamber, a swash platechamber, and a cylinder bore are formed; a drive shaft rotatablysupported by the housing; a swash plate rotatable in the swash platechamber by rotation of the drive shaft; a link mechanism providedbetween the drive shaft and the swash plate and configured to allow achange in an inclination angle of the swash plate with respect to adirection orthogonal to a rotational axis of the drive shaft; a pistonaccommodated to be reciprocatingly movable in the cylinder bore; aconversion mechanism configured to reciprocatingly move the piston inthe cylinder bore at a stroke corresponding to the inclination angleaccording to the rotation of the swash plate; an actuator capable ofchanging the inclination angle; and a control mechanism configured tocontrol the actuator, wherein the swash plate chamber communicates withthe suction chamber, the actuator includes: a fixed body fixed to thedrive shaft in the swash chamber; a movable body movable in therotational axis direction in the swash plate chamber; and a controlpressure chamber defined by the fixed body and the movable body andconfigured to introduce a refrigerant including lubricant in thedischarge chamber to thereby move the movable body, in the housing, apressure regulation chamber that communicates with the discharge chamberand the control pressure chamber and a shaft hole that allows the swashplate chamber and the pressure regulation chamber to communicate witheach other are formed, in the shaft hole, a bearing rotatably supportingthe drive shaft is arranged, a communication path that allows thepressure regulation chamber and the swash plate chamber to communicatewith each other via the bearing is provided between the drive shaft andthe shaft hole, in the communication path, an annular member arrangedaround the drive shaft is provided, the annular member includes anaperture that allows the pressure regulation chamber and the swash platechamber to always communicate with each other, and the annular membermoves in the communication path on a basis of a pressure differencebetween the pressure regulation chamber and the swash plate chamber tothereby adjust a flow rate of the refrigerant circulating through thecommunication path.
 2. The variable displacement swash plate typecompressor according to claim 1, wherein the communication path includesa recessed strip portion formed between the drive shaft and the shafthole, and the annular member is arranged in the recessed strip portion.3. The variable displacement swash plate type compressor according toclaim 1, wherein the annular member includes a first cutout extending inan axial direction parallel to the rotational axis, a second cutoutextending in the axial direction in an extending direction of the firstcutout while shifting with respect to the first cutout in acircumferential direction orthogonal to the axial direction, and a thirdcutout extending in the circumferential direction to connect the firstcutout and the second cutout, and the third cutout is the aperture. 4.The variable displacement swash plate type compressor according to claim1, wherein the bearing is a radial bearing provided between the driveshaft and the shaft hole, the annular member and the radial bearing areprovided around the drive shaft and arranged between the pressureregulation chamber and the swash plate chamber, and the radial bearingis arranged further on the pressure regulation chamber side than theannular member.
 5. The variable displacement swash plate type compressoraccording to claim 4, wherein an outer diameter of the annular member issubstantially the same as an outer diameter or an inner diameter of theradial bearing.
 6. The variable displacement swash plate type compressoraccording to claim 4, wherein an inner diameter of the annular member issubstantially the same as an outer diameter or an inner diameter of theradial bearing.
 7. The variable displacement swash plate type compressoraccording to claim 1, wherein the bearing is a radial bearing providedbetween the drive shaft and the shaft hole, the annular member and theradial bearing are provided around the drive shaft and arranged betweenthe pressure regulation chamber and the swash plate chamber, and theannular member is arranged further on the pressure regulation chamberside than the radial bearing.
 8. The variable displacement swash platetype compressor according to claim 7, wherein an outer diameter of theannular member is substantially the same as an outer diameter or aninner diameter of the radial bearing.
 9. The variable displacement swashplate type compressor according to claim 1, wherein a plurality of theannular members are provided.
 10. The variable displacement swash platetype compressor according to claim 2, wherein the drive shaft includes adrive shaft main body and a cap fit in the drive shaft main body, therecessed strip portion being recessed in the cap.